Finger protective guard for a rotary worm conveyor



June 9, 1964 P. l DINESS 3,136,407

FINGER PROTECTIVE GUARD FOR A ROTARY WORM CONVEYOR Filed Nov. 13, 1962 United States Patent I 3,136,407 FINGER PROTECTIVE GUARD FOR A ROTARY WORM CONVEYOR Poul Ivan Diness, Smedelundsgade 34, Holbaek, Denmark Filed Nov. 13, 1962, Ser. No. 237,020 Claims priority, application Denmark Nov. 18, 1961 6 Claims. (Cl. 198-213) The invention relates to a finger protective guard for a rotary worm conveyor, for example for a grain conveyor, the said worm conveyor having a part located in a tube or similar stationary member with an end edge extending transversely of the longitudinal direction of the worm conveyor and another part extending past the said edge.

Accidents often occur in connection with such worm conveyors and every year many people lose fingers as a result of these accidents. In a grain conveyor a rather long free section of the worm and a part of the stationary tube project into a quantity of grain and the worm is rotated at great speed, e.g. 800 r.p.m. Accidents occur when an operator places a finger into the grain and finger gets within the path of movement of the screw threads, his finger becomes caught by the threads and is swiftly pressed towards the end edge of the tube and severed thereby.

To avoid such accidents many different measures have been effected, substantially in the form of stationary guards surrounding the rotating worm conveyor. These devices however, reduce the capacity of the worm conveyor since, for example, bits of straw of which there will nearly always be an abundance in grain handled by a combine harvestercollect in the protective devices in front of the inlet of the conveyor and gradually bar the free flow of material to the worm.

It is an object of the present invention to provide a finger protective guard for a worm conveyor of the aforesaid kind in which complete safety against accidents is obtained without involving the the above mentioned drawbacks.

The guard according to the invention consists of a curved, plate-shaped member attached to the screw thread and covering a substantially triangular space between a peripheral line located a slight distance within the end edge of the stationary member and a part of the directly adjacent screw thread outside the stationary member.

By means of this simple design of the worm conveyor the dangerous triangular space between the end edge of the tube and the directly adjacent screw thread may be covered and by designing the plate-shaped member in such manner that there is left no open wedge between the member and the adjacent screw thread, entry between the member and the thread is blocked so that if a finger is engaged by the threads it will be passed up to the guard and subsequently deflected away from the threads.

In this design all stationary guard members are thus eliminated and the worm conveyor is made and supplied with the said plate-shaped member as a permanent component so that the user may wholly dispense with all other safety measures. 1

In accordance with the invention the curved, plateshaped member may have a front edge which extends in the longitudinal direction of the worm between two threads, and is curved in concave fashion.

In such a design a finger placed in the path of movement of the guard will be passed towards the center of the guard from either side, by which the finger will more readily be deflected from the danger zone.

An embodiment of a finger protective guard according to the invention will now be described with reference to the drawing, in which FIGURE 1 shows part of a grain conveyor, viewed from the side, partly in section and with an attached protective guard according to the invention,

FIGURE 2 is a perspective view of the protective guard, and

FIGURE 3 a section on the line IIIIII of FIGURE 1.

A grain conveyor consists of a worm conveyor rotating in part inside a stationary tube 2, a part of the worm conveyor having a number of screw threads projecting outside the end edge 3 of the tube 2 and thereby being exposed.

The worm conveyor. .1 consists of a central shaft 4 to which is welded a plate of helical shape forming the threads 5 of the worm. The worm rotates in the direction of the arrow A at a speed of approximately 800 rpm.

In the approximately triangular space formed between the end edge 3 of the tube 2 and the nearest thread 5 there is provided a curved, plate-shaped member 6 which is welded to the thread at the periphery thereof and projects slightly into the tube 2. The member 6 is thus welded to the worm along the helices 7 and 8 and has a free edge 9 inside the tube. The front or leading edge 10 of the member 6 has a concave curved shape which forms an acute angle x with the surface of helix 8 Where it contacts the same.

As will appear from FIGURE 3, the plate-shaped guard member 6 is bent at its front edge so as to provide a curved lip 11 having a convex portion which faces in the direction of rotation.

If a person during rotation of the worm places his finger between the threads the finger will be passed up into the space between the end edge 3 and the surface of helix 8 directly adjacent the end edge 3 and the finger will be deflected by the plate member 6 so that any danger of the finger being wedged between edge 3 andthe surface of the threads is eliminated.

What I claim and desire to secure by Letters Patent is:

1. A finger protective guard for a rotary worm conveyor having a helical conveyor member, and a stationary element surrounding the helical conveyor member for a portion of the length thereof, said guard comprising: a curved plate shaped member supported on the helical conveyor member and extending peripherally therearound for a portion of the length of the conveyor, said plate shape member having a portion propecting within said element and a portion projecting beyond said element to block entry between the conveyor member and the stationary element.

2. A finger protective guard as claimed in claim 1 wherein said helical conveyor member has a helical member defining threads for the conveyor member, said curved plate shaped member having a front edge which extends between adjacent threads and is of concave curved shape.

3. A finger protective guard as claimed in claim 2 comprising a curved lip on the plate shaped member at the front edge thereof.

4. A finger protective guard for a rotary worm conveyor having a helical conveyor member and a stationary element surrounding the helical conveyor for a portion of the length thereof and having a free edge from which the conveyor projects, said conveyor member having a helical plate defining threads, said guard comprising: a curved plate shape member peripherally supported on the helical plate at a location adjacent said free edge of the stationary element with a portion of said plate shape member projecting within said stationary element and a portion projecting beyond said stationary element to block entry between the free edge of the stationary element and the thread of the conveyor member immediately adjacent said edge.

5. A finger protective guard as claimed in claim 4 wherein said curved plate shape member has a front edge which extends between adjacent threads and is of concave curved shape.

6. A rotary worm conveyor comprising a helical conveyor member, a stationary element surrounding the helical conveyor for a portion of the length thereof and having a free edge from which the conveyor projects,

said conveyor member including a helical plate defining threads, a finger protective guard constituted by a curved plate shape member peripherally supported on the helical plate at a location adjacent said free edge of the stationary element with a portion of said plate shape member projecting within said stationary element and a portion projecting beyond said stationary element to block entry between the free edge of the stationary element and the thread of the conveyor member immediately adjacent said edge.

7 No references cited. 

1. A FINGER PROTECTIVE GUARD FOR A ROTARY WORM CONVEYOR HAVING A HELICAL CONVEYOR MEMBER, AND A STATIONARY ELEMENT SURROUNDING THE HELICAL CONVEYOR MEMBER FOR A PORTION OF THE LENGTH THEREOF, SAID GUARD COMPRISING: A CURVED PLATE SHAPED MEMBER SUPPORTED ON THE HELICAL CONVEYOR MEMBER AND EXTENDING PERIPHERALLY THEREAROUND FOR A PORTION OF THE LENGTH OF THE CONVEYOR, SAID PLATE SHAPE MEMBER HAVING A PORTION WITHIN SAID ELEMENT AND A PORTION PROJECTING BEYOND SAID ELEMENT TO BLOCK ENTRY BETWEEN THE CONVEYOR MEMBER AND THE STATIONARY ELEMENT. 